OFFSET
1,1
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 1.7.6 Inverse Tangent Integral, p. 57.
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
Eric Weisstein's MathWorld, Inverse Tangent Integral
Eric Weisstein's MathWorld, Polylogarithm
FORMULA
2/3*G + 5*Pi/12*log(2+Sqrt(3)), where G is Catalan's number.
Also equals i/2*(polylog(2, -i*(2+sqrt(3))) - polylog(2, i*(2+sqrt(3)))), with i = sqrt(-1).
EXAMPLE
2.3345375853123411467590386277439330048826783772509935401630054018441801...
MATHEMATICA
2/3*Catalan + 5*Pi/12*Log[2 + Sqrt[3]] // RealDigits[#, 10, 105]& // First
PROG
(PARI) default(realprecision, 100); 2/3*Catalan + 5*Pi/12*log(2 + sqrt(3)) \\ G. C. Greubel, Aug 25 2018
(Magma) SetDefaultRealField(RealField(100)); R:=RealField(); (2/3)*Catalan(R) + 5*Pi(R)*Log(2 + Sqrt(3))/12; // G. C. Greubel, Aug 25 2018
CROSSREFS
KEYWORD
AUTHOR
Jean-François Alcover, Jul 08 2014
STATUS
approved